Continuity mistake: When Sydney is tortured, she loses some teeth and a stream of blood flows out the right side of her mouth. When she returns to SD-6 and speaks with the director, the blood is gone (fair enough). Outside on the street in the following shot, the blood has returned, but there's no reason to believe that she is still bleeding.
Continuity mistake: In the parking garage, after Sydney knocks the machine pistol out of the hit man's hands, it lands with the barrel pointing away from the two of them and remains in that position during their entire fight. When Sydney grabs it off the ground, the barrel is pointing toward them.